[Federal Register Volume 66, Number 184 (Friday, September 21, 2001)]
[Rules and Regulations]
[Pages 48538-48540]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-23418]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-385-AD; Amendment 39-12444; AD 2001-19-04]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767-200 and -300 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 767-200 and -300 series 
airplanes. This action requires repetitive inspections to find 
discrepancies of the barrel nuts that attach the vertical fin to body 
section 48, and follow-on actions. For certain airplanes, this action 
requires replacement of certain bolts with new bolts. This action also 
provides for optional terminating actions for the repetitive 
inspections. This action is necessary to find and fix corroded, cracked 
or broken barrel nuts that attach the vertical fin to body section 48, 
which could result in reduced structural integrity of the vertical fin 
attachment joint, loss of the vertical fin, and consequent loss of 
controllability of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Effective October 9, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 9, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before November 20, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-385-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-385-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in this AD may be obtained from 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Craycraft, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2782; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received several reports of 
corroded and/or broken barrel nuts on certain Boeing Model 767-200 and 
-300 series airplanes. One operator indicated that cracked and bulging 
sealant of two attachment barrel nuts of the vertical fin at body 
section 48 was found on an airplane having 9,795 total flight hours and 
4,184 total flight cycles. A torque check confirmed low torque at these 
locations, and removal of the sealant revealed that both barrel nuts 
were corroded and broken. Further investigation revealed that the 
broken barrel nuts fractured due to stress corrosion cracks that 
started at corrosion pits. Examination of the attachment bolts showed 
inadequate sealant on the bolt threads and shank. The lack of sealant 
initiated galvanic corrosion between the H-11 steel barrel nut and the 
Inconel bolt, which created the corrosion pits. Nuts made of H-11 steel 
alloy are susceptible to stress corrosion cracking. Another operator 
reported cracked sealant and barrel nut corrosion on an airplane having 
20,655 total flight hours and 4,768 total flight cycles. Of the sixteen 
barrel nuts removed from that airplane and inspected, several were 
found to be corroded.
    A recent report was received of four cracked barrel nuts found on a 
Boeing Model 767-300 series airplane; three of those four were found on 
one side of the airplane. This report revealed that the issue was more 
urgent than initial reports indicated. Subsequently, another report was 
received from an operator of a Group 1 airplane(Group 1 airplanes were 
delivered with H-11 alloy steel bolts and nuts), indicating that a 
broken barrel nut was found and both the bolt and the barrel nut were 
H-11 alloy steel (no dissimilar metal). This report revealed that the 
unsafe condition also exists on Group 1 airplanes with H-11 alloy steel 
bolts installed.
    Such conditions, if not corrected, could result in reduced 
structural integrity of the vertical fin attachment joint, loss of the 
vertical fin, and consequent loss of controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 767-53-
0085, dated May 14, 1998, and Boeing Alert Service Bulletin 767-
53A0085, Revision 1, dated July 1, 1999. The service bulletins describe 
procedures for repetitive internal and external visual inspections to 
find discrepancies (i.e., cracked or damaged sealant, signs of 
corrosion damage, cracked or broken barrel nuts), of the barrel nuts 
that attach the vertical fin to body section 48, and follow-on actions. 
The follow-on actions include, but are not limited to, the following:
     Replacement of the barrel nut with a new Inconel barrel 
nut if any discrepancy is found at any barrel nut location.
     A torque check on each attachment bolt of the vertical fin 
if no discrepancy is found at any barrel nut location.
     Replacement of the barrel nut with a new Inconel barrel 
nut if a bolt can be turned during the torque check.
     Repeat of the internal and external visual inspections.
    The service bulletins also provide an optional replacement of all 
16 H-11 steel alloy barrel nuts of the vertical fin with Inconel barrel 
nuts, which would eliminate the need for the repetitive inspections.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the AD 
would require accomplishment of the actions specified in the service 
bulletin described previously, except as discussed below.

[[Page 48539]]

Differences Between Alert Service Bulletin and This AD

    While the service bulletin specifies internal and external visual 
inspections to detect discrepancies of the sealant of the barrel nuts 
that attach the vertical fin to body section 48, this AD requires 
internal and external detailed visual inspections to detect 
discrepancies of the sealant. A note has been included in this AD to 
define that inspection.
    Where the compliance time in the service bulletin specifies doing 
the internal and external visual inspections 1 year after receipt of 
the service bulletin, this AD requires those inspections be done within 
45 days after the effective date of this AD. In developing an 
appropriate compliance time for this AD, the FAA considered not only 
the manufacturer's recommendation, but the degree of urgency associated 
with addressing the subject unsafe condition, the average utilization 
of the affected fleet, and the time necessary to perform the actions. 
In light of all of these factors, the FAA finds that the compliance 
time for completing the required inspections represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.
    Although the service bulletin specifies that no more work is 
necessary for Group 1 airplanes if the H-11 steel alloy attachment 
bolts of the vertical fin have not been replaced with Inconel bolts, 
this AD requires the inspections and follow-on actions for both Group 1 
and Group 2 airplanes. This changes the applicability in the AD from 
that specified in the service bulletin, which was divided into two 
groups, one having line numbers 1 through 154 inclusive, and the other 
having line numbers 155 through 574 inclusive; to specify line numbers 
1 through 574 inclusive.
    Figure 5 of the Accomplishment Instructions of the service bulletin 
specifies that a bolt can be reinstalled if no corrosion, cracks, 
thread damage, or shank damage is found. However, for Group 1 airplanes 
with H-11 steel alloy bolts, this AD requires replacement of an H-11 
steel alloy bolt with an Inconel bolt, if an Inconel barrel nut is 
installed at that location.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications shall identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the AD is 
being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-385-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

2001-19-04  Boeing: Amendment 39-12444. Docket 2000-NM-385-AD.

    Applicability: Model 767-200 and -300 series airplanes, line 
numbers 1 through 574 inclusive, certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (g) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by

[[Page 48540]]

this AD; and, if the unsafe condition has not been eliminated, the 
request should include specific proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix corroded, cracked or broken barrel nuts that 
attach the vertical fin to body section 48, which could result in 
reduced structural integrity of the vertical fin attachment joint, 
loss of the vertical fin, and consequent loss of controllability of 
the airplane; accomplish the following:

Internal/External Detailed Visual Inspections

    (a) Do internal and external detailed visual inspections of the 
barrel nuts at the 16 locations that attach the vertical fin to body 
section 48 to find discrepancies (i.e., cracked or damaged sealant, 
signs of corrosion damage, cracked or broken barrel nuts). Do the 
inspections at the times specified in paragraphs (a)(1) and (a)(2) 
of this AD, as applicable; per Part 1 of the Accomplishment 
Instructions of Boeing Service Bulletin 767-53-0085, dated May 14, 
1998, or Boeing Alert Service Bulletin 767-53A0085, Revision 1, 
dated July 1, 1999.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) For airplanes on which the inspections specified in 
paragraph (a) of this AD have been done within the last 3 years per 
Boeing 767 Maintenance Planning Document (MPD) D622T001, Items 5380-
311-021 and 5380-312-021: Do the inspections at the later of the 
times specified in paragraphs (a)(1)(i) and (a)(1)(ii) of this AD.
    (i) Within 3 years or 6,000 flight cycles after doing the most 
recent inspection per the MPD, whichever comes first.
    (ii) Within 45 days after the effective date of this AD.
    (2) For airplanes on which the inspections specified in 
paragraph (a) of this AD have NOT been done within the last 3 years 
per Boeing 767 MPD D622T001, Items 5380-311-021 and 5380-312-021: Do 
the inspections within 45 days after the effective date of this AD.

Follow-On Actions

    (b) If no discrepancies are found as a result of any inspection 
specified in paragraph (a) of this AD: Before further flight, do a 
torque check of each of the 16 bolts in the barrel nuts that attach 
the vertical fin to body section 48 to determine if any bolt turns, 
per Part 2 of the Accomplishment Instructions of Boeing Service 
Bulletin 767-53-0085, dated May 14, 1998, or Boeing Alert Service 
Bulletin 767-53A0085, Revision 1, dated July 1, 1999.
    (1) If no bolt turns: Repeat the inspections required by 
paragraph (a) of this AD (and applicable follow-on actions) every 3 
years or 6,000 flight cycles, whichever comes first; until 
paragraphs (d) and (e) of this AD are done, as applicable.
    (2) If any bolt turns: Before further flight, do the actions 
specified in paragraphs (b)(2)(i) and (b)(2)(ii) of this AD, as 
applicable. Then repeat the inspections required by paragraph (a) of 
this AD (and applicable follow-on actions) every 3 years or 6,000 
flight cycles, whichever comes first; until paragraphs (d) and (e) 
of this AD are done, as applicable.
    (i) For all airplanes: Replace the barrel nut at that bolt with 
a new, Inconel barrel nut per Part 3 of the Accomplishment 
Instructions of the service bulletin. No further action is required 
for that barrel nut only.
    (ii) For Group 1 airplanes: If an H-11 steel alloy bolt is 
installed with the affected barrel nut, replace the bolt with a new, 
Inconel bolt per Figure 5 of the Accomplishment Instructions of the 
service bulletin. No further action is required for that bolt only.
    (c) If any discrepancy of any barrel nut is found as a result of 
any inspection specified in paragraph (a) of this AD: Before further 
flight, do the actions specified in paragraphs (c)(1) and (c)(2) of 
this AD, as applicable.
    (1) For all airplanes: Replace the affected barrel nut with a 
new, Inconel barrel nut per Part 3 of the Accomplishment 
Instructions of Boeing Service Bulletin 767-53-0085, dated May 14, 
1998, or Boeing Alert Service Bulletin 767-53A0085, Revision 1, 
dated July 1, 1999. No further action is required for that barrel 
nut only.
    (2) For Group 1 airplanes: If an H-11 steel alloy bolt is 
installed with the affected barrel nut, replace the bolt with a new, 
Inconel bolt per Figure 5 of the Accomplishment Instructions of the 
service bulletin. No further action is required for that bolt only.

Optional Terminating Actions

    (d) For all airplanes: Except as provided by paragraph (e) of 
this AD, replacement of all 16 H-11 steel alloy barrel nuts that 
attach the vertical fin to body section 48, with new, Inconel barrel 
nuts per Part 3 of the Accomplishment Instructions of Boeing Service 
Bulletin 767-53-0085, dated May 14, 1998, or Boeing Alert Service 
Bulletin 767-53A0085, Revision 1, dated July 1, 1999; ends the 
repetitive inspections required by this AD.
    (e) For Group 1 airplanes: Accomplishment of paragraph (d) of 
this AD and replacement of the H-11 steel alloy bolts having an 
Inconel barrel nut installed at the same location, with new, Inconel 
bolts per Figure 5 of the Accomplishment Instructions of Boeing 
Service Bulletin 767-53-0085, dated May 14, 1998, or Boeing Alert 
Service Bulletin 767-53A0085, Revision 1, dated July 1, 1999; ends 
the repetitive inspections required by this AD.

Spares

    (f) As of the effective date of this AD: No person shall 
install, on any airplane, an Inconel vertical fin attach bolt, 
unless an Inconel barrel nut is installed at the same location; nor 
shall any person install an H-11 steel alloy attachment nut or bolt 
on the vertical fin on any airplane.

Alternative Methods of Compliance

    (g) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office, FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Seattle ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (h) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (i) The actions shall be done in accordance with Boeing Service 
Bulletin 767-53-0085, dated May 14, 1998; or Boeing Alert Service 
Bulletin 767-53A0085, Revision 1, dated July 1, 1999. This 
incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

    (j) This amendment becomes effective on October 9, 2001.


    Issued in Renton, Washington, on September 14, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-23418 Filed 9-20-01; 8:45 am]
BILLING CODE 4910-13-P